Warning light signals are generally used to clear the right of way or to warn oncoming motorists of potential moving or stationary hazards, such as a vehicle that is stopped or a vehicle moving slower or faster than the rate of traffic. Warning light signals may also be used to provide specific directions to motorists, such as merge right or merge left or pull over. Some vehicles incorporate an arrow board or even a text matrix display to generate warning light signals to direct traffic.
The use of emergency beacons is restricted by law in many jurisdictions only for responding to an emergency, initiating a traffic stop, bona fide training exercises, or when a specific hazard exists in the road.